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Here is an image from another forum thread with the toothed washer anchored in place on the adjustable side of the bottom bracket shell. As odd as it is on the fixed side it seems even stranger to have it on the adjustable side.

Cycle is a 1972 C. Itoh fitted with a Sugino Mighty chainset, all fittings ex-works.



Let us know if you have ever learned anything additional regarding your frame of mystery...

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